This application relates to a scroll compressor wherein an eccentric pin extending forwardly of a rotating shaft shoulder is formed to have fillets at its roots that have a complex shape, to reduce the likelihood of fatigue.
Scroll compressors are becoming widely utilized in refrigerant compression applications. In a scroll compressor, a pair of scroll members each have a base with a generally spiral wrap extending from the bases. One of the two scroll members is caused to orbit relative to the other.
In one major style of scroll compressors, the one scroll member is caused to orbit by a rotating shaft being driven by an electric motor. The rotating shaft has a pin formed to extend eccentrically from an end of the shaft, and into a boss in the one scroll member. A slider block is positioned between the eccentric pin and the boss. Rotation of the shaft causes an orbiting movement of the one scroll member through the interaction of the eccentric pin and the slider block.
In the prior art, the surface between the eccentric pin and an end of the shaft, or the shaft shoulder, has fillets formed along a single radius. The eccentric pin has generally had a relatively flat surface that engages a surface in the slider block, and a circular surface extending between circumferential ends of the flat surface. There have been distinct fillets at both the circular portion and in the flat portion, however, both fillets have been formed along a single radius.
Due to size issues, the fillets have not been able to be as large as may be desirable. Because of this, the ends or tangent portions of the fillets, are relatively close to the shaft shoulder. As the forces encountered by the eccentric pin in causing the one scroll member increase, such as may be the case with increasing capacity for the scroll compressor, there is a greater likelihood of fatigue of the eccentric pin. While these issues could be addressed by increasing the size of the eccentric pin, or simply increasing the radius of the fillet, such changes would require an increase in the size of the scroll compressor. A size increase would be undesirable.